An infusion bag forms usually a shape of flat pouch, which is inconvenient in a pre-setup operation, such as a mixing injection et al, to be executed prior to the commencement of an infusion operation. In view of this, an infusion bag of a standing bag type has heretofore been proposed. Such an infusion bag of standing bag type has, at its one end, a base member, whereat the thickness of the bag is correspondingly increased, thereby allowing the bag to obtain a self-standing capability. A pre-setup operation, such as mixing injection, becomes thus possible at a self-standing state of the bag. Such a standing bag type infusion liquid container is, at a part of the base member, provided with an engaging part (an opening) for allowing the container to be suspended from an infusion stand for executing an infusion operation. As similar to an infusion process in the flat pouch type, a progress of a discharge of the infusion liquid from an infusion liquid container of the standing bag type is made possible by a progress of a collapse of the bag. As similar to the flat pouch type, the infusion liquid container of the standing bag type is collapsed also at the base end evenly as the remaining part thereof for obtaining an entirely compacted shape of the bag when disposed. See Patent Documents 1 and 2.